Serology tests look for antibodies in blood. If there are antibodies found, that indicates there has been an infection at some point. Antibodies are proteins that fight off infections. Results depend on when and if the individual may have been exposed to COVID-19 and if the person has ability to develop antibodies. The test does not rule out an active infection and does not guarantee the individual will be immune to future exposure of the COVID-19 virus. More information from CDC on serology testing for COVID-19
The antibody test is a simple blood test. We will take a blood sample and send it off to our partner lab, Clinical Pathology Laboratories. Our lab (CPL) will test the blood sample to identify the presence, if any, of antibodies. These test results alone do not confirm if you are able to spread the virus that causes COVID-19.
A positive test result indicates that antibodies to COVID-19 were detected and that the patient has potentially been exposed to COVID-19. When IgM antibodies are present, it indicates a patient has an active or recent infection with COVID-19. The presence of IgG antibodies develop later following infection, about 7-10 days after infection, it also does not exclude recenlty infected patients who are still congtagious. Just because a patient tests positive, they should not assume they are immune from contracting the virus again or that they are not contagious (if positive IgM). It is also possible a patient may test positive for antibodies but does not havce or have ever had symptoms of COVID-19, this is known as having asymptomatic (no symptoms) infection.
A negative test result means antibodies (IgG or IgM) were not present in the blood specimen. However, a negative test result does not necessarily rule out SARS-CoV-2, particularly in those who have been in contact with the virus, and should not be used as the sole basis for treatment or ruling out an active infection. Patients who are tested early after infection may not have detetable IgM antibody present despite an active infection. Also, not all patients will develop IgM and/or IgG response to COVID-19 infection, which means you may have had the infection but did not produce any antibodies. Lastly, it is important to know there is still an error rate with testing, meaning false negatives are possible. Some people people may take even longer to develop antibodies (normally 1-3 weeks) and some people may not develop antibodies.
When IgM antibodies are present, they can indicate that a patient has an active or recent infection with SARS-CoV-2 (COVID-19). If a patient’s blood indicates IgG antibodies, it means antibodies developed after the infection (about 7-10 days after infection). When IgG antibodies are present it indicates a past infection but does not exclude recetly infected patients who are still contagious, especially if there is a detection of IgM antibodies.
Potential risks include:
Potential benefits include:
This test is FDA-accepted, which means that it is not yet approved or cleared. However, when there are no available FDA-approved or cleared tests, the FDA can make tests available under an emergency access mechanism called Emergency Use Authorization (EUA). This EUA will remain in effect for the duration of the COVID-19 declaration.
We are currently using Clinical Pathology Laboratories (CPL). We will also soon be using Quest Diagnostics. The test method used is the Abbott Architect chemiluminescent microparticle immunoassay (CMIA).
Our lab, Clinical Pathology Laboratories, uses Abbott Architect chemiluminescent microparticple immunoassay (CMIA) for the qualitative detection antibodies to SARS-CoV-2. The assay is designed to detect antibodies to the nucelocapsid protein of SARS-CoV-2 in serum and plasma from patients with signs and symptoms of infection who are suspected of coronavirus diesase (COVID-19) or in serum and plasma of subjects that may have been infected by SARS-CoV-2.
The CDC (Centers for Disease Control and Prevention) is looking at the data from antibody tests conducted to estimate the total number of people who have been infected with COVID-19 in the United States.
Updated 5/6/2020. Please note that information on serological antibody testing for COVID-19 is evolving and the information listed above may change. Information listed on this page has been sourced from www.CDC.gov, www.fda.gov and Clinical Pathology Laboratories.